1. Technical Field
The present invention relates to an electro-optical device and an electronic apparatus.
2. Related Art
In general, a touch panel is provided on a topside of a display device such that a user can select information displayed on a screen of the display device by using his/her finger or an object. The touch panel detects a touch position at which the user touches the touch panel using his/her finger or the object, and receives information regarding the touch position on the display device as an input signal. The touch panel is then driven on the basis of the input signal. Display devices with touch panels are being increasingly used since an additional input device, such as a keyboard or a mouse, which is connected to the display device, is not needed.
An apparatus has been developed in which a liquid crystal panel has a touch panel function. For example, a photo-detection touch panel is known in which a TFT (Thin Film Transistor) substrate has a touch panel function (for example, see JP-A-2006-238053). In addition, a liquid crystal display is known in which a change in liquid crystal capacitance when being touched is read for touch sensing (for example, JP-A-2007-48275).
When a touch sensor (touch panel) is provided on a liquid crystal panel, the panel increases in thickness. According to the technology disclosed in JP-A-2006-238053, if a sensing area, which is a non-display area, is provided below a black matrix (BM), photo-detection sensitivity is lowered. If the sensing area is provided outside the BM, contrast is lowered. That is, it is difficult to satisfactorily perform both display and sensing.
According to the technology disclosed in JP-A-2007-48275, a sensing area is disposed near display pixels. Since a sensing signal is generated by reading a change in capacitance, each electrode preferably has a large area. However, the larger the area of each electrode is, the lower the aperture ratio of a display area is. Furthermore, if the sensing area has a high resolution, the aperture ratio is low.